The expression (3-7i)^2 is equivilant to? i know what the answer is im just not sure how to get it please help

Answer 1

Just expand it
(3-7i)^2
= (3-7i)(3-7i)
= 9 - 42i + 49i^2 , but i^2 = -1
= 9 - 42i - 49
= -40 - 42i

Answer 2

okay thank you